Category Archives: Animal Diseases

Traditional knowledge key to managing outbreaks of Rift Valley fever: Study points out important role livestock keepers play in veterinary surveillance

Posted on by
Reply

Orma Boran cattle crossing a river in Kenya

Orma Boran cattle crossing a river in Kenya. Cattle and people both can be infected with Rift Valley fever (Photo credit: R Dolan)

Livestock researchers say the traditional knowledge of local pastoralists in East Africa needs to be included in programs to better control livestock diseases in the region.

Somali and Maasai herder early warning systems both were key in identifying the risk factors and symptoms of Rift Valley fever in an outbreak in 2006/7.

Rift Valley fever is an acute viral zoonosis spread by mosquitoes. It primarily affects domestic livestock such as cattle, camels, sheep and goats, but can also infect, and kill, people, especially those handling infected animals.

First isolated in humans in the Rift Valley region of Kenya in 1930, until the 1970s Rift Valley fever was reported mainly in southern and eastern Africa, primarily Kenya, where it was considered an animal disease, despite sporadic human cases. But after the 1970s, explosive outbreaks occurred in human populations throughout Africa, Indian Ocean states and the Arabian Peninsula. Epidemics in Egypt in 1977/8 and in Kenya in 1997/8 each killed several hundred people. Another outbreak in Kenya in 2006/7 killed more than 100 people.

In East Africa, Rift Valley fever outbreaks have coincided with heavy rainfall and local flooding, which can lead to expansion of mosquito populations. In an assessment made to review lessons from the 2006/7 outbreak in East Africa carried out by scientists from the International Livestock Research Institute (ILRI) and the Kenyan and Tanzanian departments of veterinary services, researchers found that Somali pastoralists of northeastern Kenya accurately assessed the likelihood of an outbreak based on their assessments of key risk factors, and they did so long before veterinary and public health interventions began. The study also looked at the experiences of Maasai herders of northern Tanzania, who accurately recognized symptoms such as high abortion rates as indicating the presence of the infection in their herds.

Among the environmental factors the Somali communities noticed as likely to lead to an outbreak is an increase in rainfall (usually accompanied by floods) and an increase in mosquitoes. Both preceded the 2006/7 outbreak and had been present in the last outbreak of Rift Valley fever in the region in 1997/8. The Somalis also accurately associated a ‘bloody nose’, or Sandik, in their animals with Rift Valley fever.

The role of this traditional knowledge in predicting Rift Valley fever is the subject of a paper, ‘Epidemiological assessment of the Rift Valley fever outbreak in Kenya and Tanzania in 2006 and 2007’, published in the August 2010 supplement of the American Journal of Tropical Medicine and Hygiene.

The authors say that Somali pastoralists are particularly able to predict not only the symptoms of Rift Valley fever in their animals but also the likelihood of an outbreak of the disease. Indeed, observations by local communities in risk-prone areas were often more timely and definitive than the global early warning systems in use at the time of the 2006/7 outbreak.

‘Timely outbreak response requires effective early warning and surveillance systems. This study points out the important role that livestock keepers can play in veterinary surveillance,’ the authors say.

As a result of the experiences of the 2007 outbreak, the authors recommend adopting new forecasting models and surveillance systems ‘that place more emphasis on climatic information [to] increase the lead time before events and enhance the ability of decision-makers to take timely action.’

The researchers also say that outbreaks of Rift Valley fever could be managed better if disease control workers were able to run models that combined economic with epidemiologic factors. With such models, they could better determine the benefits of implementing various disease surveillance and control methods, and the best times to implement each method selected for each circumstance.

This piece is adapted from the article New journal article: An assessment of the regional and national socio-economic impacts of the 2007 Rift Valley fever outbreak in Kenya by Tezira Lore, communications specialist for ILRI’s Markets Theme.

To read the complete report and its recommendations please visit http://www.ajtmh.org/cgi/content/abstract/83/2_Suppl/65/

A related ILRI news article addresses the full effects of the 2006/7 Rift Valley fever outbreak in East Africa, including the national and regional socioeconomic impacts of the outbreak and its effects on human and animal health.

Assessing the full costs of livestock disease: The case of the 2007 outbreak of Rift Valley fever in Kenya

Posted on by
Reply

Bullish market

Livestock market in Garissa, in northeastern Kenya. Closure of the cattle market and disruption of cross-border cattle trade with Somalia due to outbreaks of livestock disease can worsen food insecurity among the pastoralists and agropastoralists on both sides of the border. (Photo credit: Tze-Yun Soh)

Rift Valley fever is a mosquito-transmitted zoonotic disease that harms both human health and livestock production. It can also induce large, often overlooked, economic losses among many other stakeholders in the livestock marketing chain.

A new paper published by ILRI scientists Karl Rich and Francis Wanyoike assesses and quantifies the multi-dimensional socio-economic impacts of a 2007 outbreak of Rift Valley fever in Kenya. The study is based on a rapid assessment of livestock value chains in the northeast part of the country and a national macroeconomic analysis. As would be expected, the study results show losses among producers in food security and incomes. But the researchers also found significant losses occurred among other downstream actors in the value chain, including livestock traders, slaughterhouses, casual labourers, and butchers, as well as among those in non-agricultural sectors. To better inform policy and decision making during animal health emergencies, the authors argue that we should widen our focus to include analyses that address the multitude of economic losses resulting from an animal disease.

The authors write:

‘Rift Valley fever has had significant impacts on human and animal health alike in East Africa and the Middle East. Past outbreaks in South Africa (1951), Egypt (1977/78), Kenya (1997), and Saudi Arabia (1998–2000) resulted in the cumulative loss of thousands of human lives. The 2000 outbreak in Saudi Arabia led to the imposition of trade bans of live animals from the Horn of Africa (Ethiopia, Somalia, and Kenya) that had devastating economic impacts: one study estimated that total economic value-added in the Somali region of Ethiopia fell by US$132 million because of these trade bans, a 42% reduction compared with normal years . . . .

‘In 2007, Rift Valley fever returned to East Africa, impacting both Kenya and Tanzania. Specifically hard hit by this latest outbreak were the pastoral communities of the northeastern part of Kenya. In this region, livestock serve an important livelihood function for pastoralists, with livestock trade representing over 90% of pastoral incomes . . . . Moreover, northeastern Kenya has the highest incidence of poverty within Kenya, with poverty rates of approximately 70% in 2004 . . . .

‘An overlooked component in the socio-economic analysis of animal diseases is the multiplicity of stakeholders that are affected. Rift Valley fever does not just affect producers, but also impacts a host of other service providers within the livestock supply chain and other parts of the larger economy. Cumulatively, these downstream impacts can often dwarf the impacts of the disease at the farm level, but public policy tends to concentrate primarily on losses accruing to producers. The failure to capture these diverse impacts may have important implications on the evolution and control of disease that may accentuate its impact.

‘The 2007 Rift Valley fever outbreak in Kenya had wide-ranging impacts on the livestock sector and other segments of the economy that are often overlooked in the analysis of animal disease. These impacts included production impacts, employment losses (particularly for casual labor), and a reduction in operating capital among slaughterhouses and butchers that slowed the recovery of the livestock sector once the disease had abated. On a macroeconomic basis, we estimated that Rift Valley fever induced losses of over Ksh 2.1 billion (US$32 million) on the Kenyan economy, based on its negative impacts on agriculture and other sectors (transport, services, etc.) alike.’

Read more: An Assessment of the Regional and National Socio-Economic Impacts of the 2007 Rift Valley Fever Outbreak in Kenya, by Karl Rich and Francis Wanyoike. Rich is on joint appointment with ILRI and the Norwegian Institute of International Affairs, in Oslo. ILRI researcher Wanyoike is based in Nairobi. Their paper is published in the American Journal of Tropical Medicine and Hygiene, 83(Suppl 2), 2010, pp. 52–57.

Need for delivery networks for East Coast fever vaccine highlighted in audio interview

Posted on by
Reply

ITM Vaccine

East Coast fever is a major livestock disease in eastern, central and southern Africa. Transmitted by ticks infected with a protozoan parasite (Theileria  parva), it kills over 1 million animals each year, damaging livelihoods of poor livestock keepers and farmers in 11 countries. Researchers from organizations such as the International Livestock Research Institute (ILRI) are working to find innovative ways to protect African livestock against this and other ‘orphan’ livestock diseases.

One of the successes in the efforts to fight East Coast fever has been the development of a ‘live’ vaccine, which includes the whole parasite, weakened so as not to cause severe disease thatcame after over 30 years of research by organizations including ILRI and the Kenya Agricultural Research Institute. This long-term research was funded by UK Department for International Development and other donors of the Consultative Group on International Agricultural Research. The vaccine is now registered in Kenya, Malawi and Tanzania and its widespread use is being promoted so that it can give protection to the animals on which many poor people in these countries depend.

In the following audio interview, John McDermott, Deputy Director General-Research at ILRI, speaks in Nairobi of the need ‘to develop networks that can distribute and deliver’ the vaccine to those who need it, which should encourage its widespread use. This interview, produced in July 2010 by AFGAX Radio (http://www.agfax.net), also shares the expectations of a veterinarian from Kenya and a farmer from Tanzania of how the vaccine will help livestock keepers.

To listen to the interview, visit: http://www.agfax.net/radio/detail.php?i=353

More information about the East Coast fever live vaccine is available in the following article.

Edinburgh-Wellcome-ILRI project addresses neglected zoonotic diseases in western Kenya

Posted on by
2

Woman Feeding Cow

‘Neglected diseases are diseases of neglected peoples’—Eric Fèvre

Animals and people live close together throughout the developing world. Chickens, goats, pigs, cows and other farmed animals range freely in and out of rural homesteads as families go about their daily lives. This space-sharing by people and their livestock makes good use of the small plots of land managed by the world’s many smallholder farmers; food that might otherwise go to waste can be fed to the animals, for example, while animal manure feeds the cropland by fertilizing it. Most of the world’s smallholder farmers depend on their animals for milk, meat and eggs to feed their families, with the surplus generating much-needed regular household income.

However, such close proximity to their animals puts many people at risk of ‘zoonotic’ diseases, which are those transmitted between people and animals. Remarkably, more than 60% of all human diseases are infections they can get from animals and more than 70% of today’s emerging diseases, such as bird flu, are zoonotic.

Because human and animal health are particularly intertwined in poor countries where people and livestock live in such close proximity, efforts to improve human health in the developing world need to focus on improving animal as well as human health. This makes it necessary for medical and veterinary experts to collaborate and for livestock farmers and herders to be made aware of the disease risks their animals pose to the health of their households.

A project begun in 2009 and funded by the Wellcome Trust, with other support from the International Livestock Research Institute (ILRI), is studying neglected zoonotic diseases and their epidemiology to raise levels of health in poor rural communities. The project, People, Animals and Their Zoonoses, is based in Kenya’s Busia District, which sits on the country’s western border, with Uganda.

Eric Fèvre, who is working jointly for the International Livestock Research Institute (ILRI) and the University of Edinburgh, is the project’s principal investigator and leader. Fèvre says this study is important.

‘Zoonotic diseases are a great burden on poor communities’, Fèvre says. ‘In a poor household where animals and people are in regular close contact, there is a significant chance of zoonotic diseases spreading. Typically in such areas, animals have access to human waste, there is little preventative health services for livestock and there is poor-quality food and forage for people and animals.’

With insufficient and/or unreliable health infrastructure and with many poor people not readily seeking professional medical attention, these diseases often go underreported or misdiagnosed. Complicating and aggravating this already serious health situation, he says, is that ‘in some cases, other non-zoonotic infections may already be present.’

Furthermore, as reported in the May 2010 issue of Veterinary Record, Fèvre says:

‘While malaria is undoubtedly a very serious health issue, its overdiagnosis hides many other problems. To compound this, people in marginalised communities can easily fall off the policy radar – many may be born, live and die without official record being made of them and, as such, they have a weak, or nonexistent, political voice. Thus, while the diseases are grouped as “neglected zoonotic diseases,” it would be equally correct to identify them as “diseases of neglected populations”.’

The Kenya zoonotic study is a four-year project that brings together ILRI scientists in Kenya with researchers from the School of Biological Sciences at the University of Edinburgh and from the Kenya Medical Research Institute, the latter of whom are already working in much of Kenya’s Western and Nyanza provinces. These epidemiologists, veterinarians, medical health professionals and laboratory technologists will visit over 500 homesteads in Busia to collect data and samples from people and livestock; those people found ill will be treated or referred to specialists.

The project data will be used to quantify the place of zoonoses in the context of other infectious diseases and to refine our understanding of factors that put people and livestock at risk. The study team also aims to come up with diagnostic tests that can be used in the field and to design cheap, easy-to-implement health interventions for both people and livestock. The project is focusing on bovine tuberculosis, cysticercosis, brucellosis, Q-fever, Rift Valley fever and trypanosomiasis (in cattle) /sleeping sickness (in people) and their impacts on both livestock and the people.

The results of this project are expected not only to improve the health aspects of the relationship between people and their livestock in we